<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        ol{
            border:solid 1px #666666;
            list-style: none;
        }
        li{
            margin: 5px;
        }
        li#l1,li#l2{
            float:left;
        }
        li#l3{
            float:right;
        }

    </style>
</head>
<body>
<ol>
    <li id="l1"><a href="#">链接1</a></li>
    <li id="l2"><a href="#">链接2</a></li>
    <li id="l3"><a href="#">链接3</a></li>
    <li id="l4">&nbsp;</li>
</ol>
其它内容
</body>
</html>